Two Methods For Repairing Seawalls

Posted on: 23 March 2016

Water is one of the most persistent of Mother Nature's forces. Water can wear through clay, rock and even cement. Creating a structure to stand up indefinitely to the force of constant water pressure is impossible. Even the strongest water retaining structures, such as seawalls, break down over time.

There are proven methods for stabilizing seawall structures that have been weakened by constant exposure to the sea. Two of the main ones are explained here.

Jet Grouting

Jet grouting is a method to shore up seawall structures by injecting grout behind the structure that is weakening. The idea is that the grout will get into the gaps that have formed over time in the existing seawall. Once the grout hardens, it will form a solid barrier to the sea.

The grout is created while the injection is occurring from a mixture of materials injected into the spaces by the drill rods and the soil that is displaced as the drilling occurs. The slurry eventually hardens into a cement created during the drilling process. The result is a solid, if inelegant, cement wall to shore up the existing seawall.

Placing Cement Shafts

The other approach is to drill new shafts and pour cement into those shafts to form a structure to support the existing sea wall. These shafts would be overlapping so that they would eventually connect together to form a supporting concrete wall.

The drilled shafts are usually done in series, so that they can properly overlap. The concrete for each shaft can be poured once each shaft is completed. Eventually, after each shaft has been drilled, all of the concrete will create a solid, supporting structure behind the existing structure.

Repairing or Replacing the Facing

Once the existing seawall has been stabilized, it is time to repair or replace the facing. The decision to repair or replace really depends upon how damaged the existing wall is.

To effect repairs or to replace the wall, the water has to be drained away from the seawall. Water can be drained by temporarily damming the water that normally is held back by the seawall. Creating a temporary dam is a huge undertaking with methods dependent upon the unique circumstances of each construction project.

Seawall repair is all about stabilizing the existing structure instead of tearing it down and starting from scratch. Jet grouting and drilling new shafts are proven methods for stabilizing existing seawalls.